Learn by doing, that's my motto. Nice images, some thoughts:
I personally think they're just a bit underexposed, a little more light on the face would be good (#3 is actually really close, its my favorite).
Don't have such a drastic tilt to your framing, canting is generally like anything in photography: a little bit is good, too much is overwhelming (yes this rule is absolutely made to be broken but considering your subject and the mood you're creating I think something more subtle would work better)
You almost completely lose his hair in the background, a second light or even a reflector could help bring this out and offer a little more separation from the background.
Look forward to seeing more
